I have purchased twice from forums before this rule was implemented, paid as soon as I received a PayPal link and would hope that the guys I bought from would agree that we enjoyed very smooth transactions. However, I have no posts outside of the classifieds section, so presumably can no longer make future purchases as they don't count.
I'm by no means against tightening things up, but I also have little to contribute to discussions outside of the classifieds - as a relative n00b, I don't have enough experience to help others, but I don't really have any questions that I haven't been able to solve just by reading existing threads. It would probably therefore take me a while to amass 10 posts without spamming. Not an issue of PHDs, it's quality vs quantity - I don't want to make irrelevant posts to artificially increase my count and therefore look like the dodgy dudes this system is supposed to prevent.
I would fully support some sort of PayPal verification system or vote of confidence from those with whom I have already done business.
Just my tuppence.